Not much to air flow on these things. Air goes into the case, gets pushed up through the transfer ports to the combustion chamber and out the exhaust.
As said, pull the rv cover and take a look. Clearances are pretty tight in the case so hopefully the big pieces are pinned against the crank before anything got sucked into the case.
Check your rotary valve for a damaged/bent leading edge.
ALWAYS disconnect you battery before working on the machine.
Good luck, let us know what you find.